Category Archives: Science

Why Does the Moon Appear Larger on the Horizon?

Why does the Moon look so huge on the horizon?

If you’ve ever seen the Moon rising over the horizon, looking so fat and looming that you felt like you could fall right into it, then you’ve been a victim of the famous Moon Illusion. And it is an illusion, a pervasive and persuasive one.
…
When the Moon is on the horizon, your brain thinks it’s far away, much farther than when it’s overhead. So the Ponzo Illusion kicks in: your brain sees the Moon as being huge, and it looks like you could fall into it. The Illusion works for the Sun, too. In fact, years ago I saw Orion rising over a parking lot, and it looked like it was spread across half the sky. It’s an incredibly powerful illusion.

Oddly enough, when it’s on the horizon, the Moon actually is farther away than when it’s overhead. Not by much, really, just a few thousand kilometers (compared to the Moon’s overall distance of about 400,000 kilometers).
…
So the Moon Illusion is just that. It’s not the air acting like a lens, or foreground objects making it look big by comparison. It’s just the way we see the shape of the sky together with the well-known Ponzo Illusion.
..
Science taking something we perceive as real, breaking it down, and showing it to be an interesting but decidedly unreal illusion? Well, that’s what science does! It helps us not only understand the world better, but it also makes the world cooler, too.

Ironmaking at the National Museum of Science and Technology in Stockholm

Joakim Storck discusses pre–industrial Swedish and Japanese techniques for iron and sword making from a museum demonstration at Tekniska museet. Ironmaking at the National museum of science and technology, Stockholm 2005

Bricklaying is a messy story. The mortar consists of clay, sand and horse manure (if available), mixed with water to a fairly loose batter. The best finish is obtained if you work with your hands as the mortar is placed on, and smears with water so that the surface becomes smooth and fine. When then furnace is ready, it is dried through slow heating by wood without blasting, until the moist has been driven out of the mud. At this stage, heating should be quite cautious in order to avoid cracking.

Then, on Friday September 9, we went again with a fully loaded trailer from Dalarna in the direction of Stockholm. More than a few people were probably turning their heads when we passed, because the trailer was dominated by a large bellow — our newly built two chamber bellow with an estimated bladder capacity of up to 800 litres per minute. In addition, we brought fire wood, iron rods, pliers, some stumps and other stuff needed for the furnace operation.
…
We made one run each on Saturday and Sunday. Each time we charged a total of about 10kg ore added in amounts of about 1kg every 20 minute. For each charge, we added about twice the amount of charcoal. Discharging of the loupe was scheduled for two o’clock, and by that time a fairly large crowd had gathered to see the show. This time we managed to get the loupe out of the furnace without too much trouble. Worse was that the process took longer than expected, but the crowd seemed to be patient and people stayed around until the end.

Science Courses for the Next Generation

During the last three years, the Howard Hughes Medical Institute (HHMI) has recruited 44 colleges and universities across the country to join its Science Education Alliance (SEA), which is changing how freshmen learn about science by providing them with an authentic, classroom-based research experience. Now professors from three schools offering the SEA course will help create the next generation of research-based courses that will extend the program’s reach to upperclassmen.

These “SEA sabbaticals” are another step toward HHMI’s long-term goal of making the SEA a resource for science educators nationwide. When HHMI unveiled the SEA program in 2007, it committed $4 million over four years to the development and rollout of the Alliance’s first course: the National Genomics Research Initiative. That year-long course has enabled freshmen to make real discoveries by doing research on phage, which are viruses that infect bacteria. The research-based laboratory course provides beginning college students with a true research experience that is teaching them how to approach scientific problems creatively and will hopefully solidify their interest in a career in science.

The freshmen students in the SEA course work closely with faculty to design experiments and make scientific discoveries. Many say the experience has changed their view of science. But it soon became apparent that one set of courses would not be enough to continue challenging students as they progressed through college. So HHMI decided to look for creative solutions to that problem.

HHMI invited the 27 schools currently participating in the SEA to apply, and three were accepted to develop new courses. These new projects are focused on designing a curriculum that will pick up where the virus genomics class ends.

Faculty from Cabrini College in Radnor, Pennsylvania, will develop a cellular and molecular biology course in which students will examine phage genes and determine which are essential for the virus’s survival. In a biochemistry course, students will purify and characterize the proteins produced by the genes to determine their function.

University of Louisiana at Monroe’s team will create three modules that could be used in several courses for juniors and seniors. In one, they will create lessons in which students develop methods to determine how their phages reproduce after they enter bacteria. Students would look at genetic markers to determine how phages should be classified into related “clusters” in a second module. Students taking the third course would explore the best way to determine whether genes are essential to the survival of the virus.

University of Puerto Rico, Cayey faculty will create a course to help students examine and characterize various phage proteins. Proteins of interest include those that make up the virus’s protective coating, and those that are activated once infection has begun.

HHMI continue to fund huge amounts of great work in science.

Full press release: Science Education Alliance Builds Research Courses for the Next Generation

Trying to Find Pest Solutions While Hoping Evolution Doesn’t Exist Doesn’t Work

How To Make A Superweed

Melander wondered why some populations of scales were becoming able to resist pesticides. Could the sulfur-lime spray trigger a change in their biology, the way manual labor triggers the growth of callouses on our hands? Melander doubted it. After all, ten generations of scales lived and died between sprayings. The resistance must be hereditary, he reasoned. He sometimes would find families of scales still alive amidst a crowd of dead insects.

This was a radical idea at the time. Biologists had only recently rediscovered Mendel’s laws of heredity. They talked about genes being passed down from one generation to the next, yet they didn’t know what genes were made of yet. But they did recognize that genes could spontaneously change–mutate–and in so doing alter traits permanently.
…
In the short term, Melander suggested that farmers switch to fuel oil to fight scales, but he warned that they would eventually become resistant to fuel oil as well. In fact, the best way to keep the scales from becoming entirely resistant to pesticides was, paradoxically, to do a bad job of applying those herbicides. By allowing some susceptible scales to survive, farmers would keep their susceptible genes in the scale population. “Thus we may make the strange assertion that the more faulty the spraying this year the easier it will be to control the scale the next year,” Melander predicted.
…
What’s striking is how many different ways weeds have found to overcome the chemical. Scientists had thought that Roundup was invincible in part because the enzyme it attacks is pretty much the same in all plants. That uniformity suggests that plants can’t tolerate mutations to it; mutations must change its shape so that it doesn’t work and the plant dies. But it turns out that many populations of ryegrass and goosegrass have independently stumbled across one mutation that can change a single amino acid in the enzyme. The plant can still survive with this altered enzyme. And Roundup has a hard time attacking it thanks to its different shape.
…
Another way weeds fight off Roundup is through sheer numbers. Earlier this year an international team of scientists reported their discovery of how Palmer amaranth resists glyphosate. The plants make the ordinary, vulnerable form of the enzyme. But the scientists discovered that they have many extra copies of the gene for the enzyme–up to 160 extra copies, in fact.
…
What makes the evolution of Roundup resistance all the more dangerous is how it doesn’t respect species barriers. Scientists have found evidence that once one species evolves resistance, it can pass on those resistance genes to other species. They just interbreed, producing hybrids that can then breed with the vulnerable parent species.

Another great article from Carl Zimmer.

Bee Colonies Continue to Collapse

The activity to find the causes of Colony Collapse Disorder provides a view into the scientific inquiry process of complex living systems. Finding answers is not easy.

Fears for crops as shock figures from America show scale of bee catastrophe

Disturbing evidence that honeybees are in terminal decline has emerged from the United States where, for the fourth year in a row, more than a third of colonies have failed to survive the winter.

The decline of the country’s estimated 2.4 million beehives began in 2006, when a phenomenon dubbed colony collapse disorder (CCD) led to the disappearance of hundreds of thousands of colonies. Since then more than three million colonies in the US and billions of honeybees worldwide have died and scientists are no nearer to knowing what is causing the catastrophic fall in numbers.
…
It is estimated that a third of everything we eat depends upon honeybee pollination.
…
Potential causes range from parasites, such as the bloodsucking varroa mite, to viral and bacterial infections, pesticides and poor nutrition stemming from intensive farming methods.
…
“We believe that some subtle interactions between nutrition, pesticide exposure and other stressors are converging to kill colonies,” said Jeffery Pettis, of the ARS’s bee research laboratory.
…
“It’s getting worse,” he said. “The AIA survey doesn’t give you the full picture because it is only measuring losses through the winter. In the summer the bees are exposed to lots of pesticides. Farmers mix them together and no one has any idea what the effects might be.” Pettis agreed that losses in some commercial operations are running at 50% or greater.

High Levels of Miticides and Agrochemicals in North American Apiaries: Implications for Honey Bee Health (open access paper on the topic, March 2010)

The 98 pesticides and metabolites detected in mixtures up to 214 ppm in bee pollen alone represents a remarkably high level for toxicants in the brood and adult food of this primary pollinator. This represents over half of the maximum individual pesticide incidences ever reported for apiaries. While exposure to many of these neurotoxicants elicits acute and sublethal reductions in honey bee fitness, the effects of these materials in combinations and their direct association with CCD or declining bee health remains to be determined.

Antibiotics, Farming and Superbugs

Antibiotics and farming – how superbugs happen

Provocative new research from Boston University’s medical school and department of biomedical engineering now suggests, though, that multi-drug resistance can be acquired in one pass, through a different mutational process triggered by sublethal doses of antibiotics – the same sort of doses that are given to animals on farms.

In earlier work, the authors found that antibiotics attack bacteria not only in the ways they are designed to (the beta-lactams such as methicillin, for instance, interfere with staph’s ability to make new cell walls as the bug reproduces, causing the daughter cells to burst and die), but also in an unexpected way. They stimulate the production of free radicals, oxygen molecules with an extra electron, that bind to and damage the bacteria’s DNA.

That research used lethal doses of antibiotics, and ascertained that the free-radical production killed the bacteria. In the new research, the team uses sublethal doses, and here’s what they find: The same free-radical production doesn’t kill the bacteria, but it acts as a dramatic stimulus to mutation, triggering production of a wide variety of mutations

Webcast on Finding the Missing Memristor

Very interesting lecture on finding the missing memristor by R. Stanley Williams. From our post in 2008:

How We Found the Missing Memristor By R. Stanley Williams:

For nearly 150 years, the known fundamental passive circuit elements were limited to the capacitor (discovered in 1745), the resistor (1827), and the inductor (1831). Then, in a brilliant but underappreciated 1971 paper, Leon Chua, a professor of electrical engineering at the University of California, Berkeley, predicted the existence of a fourth fundamental device, which he called a memristor.

Evidence that Refined Carbohydrates Threaten the Heart

More Evidence that Refined Carbohydrates, not Fats, Threaten the Heart

Eat less saturated fat: that has been the take-home message from the U.S. government for the past 30 years. But while Americans have dutifully reduced the percentage of daily calories from saturated fat since 1970, the obesity rate during that time has more than doubled, diabetes has tripled, and heart disease is still the country’s biggest killer. Now a spate of new research, including a meta-analysis of nearly two dozen studies, suggests a reason why: investigators may have picked the wrong culprit. Processed carbohydrates, which many Americans eat today in place of fat, may increase the risk of obesity, diabetes and heart disease more than fat does – a finding that has serious implications for new dietary guidelines expected this year.
…
Right now, Post explains, the agency’s main message to Americans is to limit overall calorie intake, irrespective of the source. “We’re finding that messages to consumers need to be short and simple and to the point,” he says. Another issue facing regulatory agencies, notes Harvard’s Stampfer, is that “the sugared beverage industry is lobbying very hard and trying to cast doubt on all these studies.”

The medical studies about what food to eat to remain healthy can be confusing but some details are not really in doubt. So while the exact dangers of processed carbohydrates, fat, excess calories and high fructose corn syrup may be in question their is no doubt we, in the USA, are not as healthy as we should be. And food is a significant part of the problem. Eat food, not too much, mostly plants and get enough exercise is good advice.

Friday Fun: Amazing Goal

This amazing goal illustrates what is possible with an amazing football (soccer) player and some physics.

A single Liter of Seawater Can Hold More Than One Billion Microorganisms

Mat of microbes the size of Greece discovered on seafloor

mighty microbes, which constitute 50 to 90 percent of the oceans’ total biomass, according to newly released data.

These tiny creatures can join together to create some of the largest masses of life on the planet, and researchers working on the decade-long Census of Marine Life project found one such seafloor mat off the Pacific coast of South America that is roughly the size of Greece.

A single liter of seawater, once thought to contain about 100,000 microbes, can actually hold more than one billion microorganisms, the census scientists reported. But these small creatures don’t just live in the water column or on the seafloor. Large communities of microscopic animals have even been discovered more than one thousand meters beneath the seafloor. Some of these deep burrowers, such as loriciferans, are only a quarter of a millimeter long.

“Far from being a lifeless desert, the deep sea rivals such highly diverse ecosystems as tropical rainforests and coral reefs,”
…
Microbes help to turn atmospheric carbon dioxide into usable carbon, completing about 95 percent of all respiration in the Earth’s oceans…